It has been recognized that treatment of burns and other lesions and wounds is enhanced by isolating the affected area and treating it with oxygen or other therapeutic gases in a controlled manner. When the affected area is on a limb, efforts have been made to provide a sealed treatment chamber about the limb by a flexible bag having its closed end at the extremity end of the limb, and its open end secured to an intact skin area near the opposite end of the limb as to provide a hermetic seal. The most common method of gas delivery into the bag chamber has been through a centrally located inlet port, but this can result in a concentration of therapeutic effect in one area and too little in other areas. This is frequently most evident during gas heating or chilling treatment modes. Prior art devices have generally attempted to solve this problem by employing a variety of throttling or flow metering methods. However these methods have not solved the basic problems of unequal temperature distribution along the limb surface, stagnant air pockets adjacent the bag extremities, and stagnant pockets of high relative humidity gas which promote the growth of certain microbes requiring the operators to somehow clean the interior surface of the bag or replace the bag.
Those isolator bag systems which introduce therapeutic gases at more than one inlet rely upon special external arrangements of tubes and valves creating gas flow patterns which are unduly complex and cause problems with gas flow regulation. Most often the prior art devices have included a rigid frame or support arm which not only is an additional weight for the patient to bear, but also creates an intrusive structure at the bed site.
Prior isolator bags, when sealed to the patient's limb, have been attached to the skin at or near 90.degree. to the length of the limb. The resulting circumferential compression is likely to have a tourniquet effect causing compression of a vascular bundle, thereby impeding venous, lymphatic or arterial flow.
Previous isolator bags have been relatively difficult to install without contacting the affected areas and causing discomfort to the patient.